The present invention relates generally to a safety system for eliminating any risk of liquids being carried to the torch nose-piece or to the vent hole, during burning or dispersion of the gases associated with the production or with the treatment of hydrocarbons on land and off-shore.
The present invention relates to a safety system for eliminating any risk of liquids being carried to the torch nose-piece during burning of the gases associated with the production of hydrocarbons, more especially off-shore.
Generally, it is known that liquids carried along in the nose-piece of a torch, particularly resulting from choking up of the gas/oil or gas/condensate separators, constitutes a serious danger in hydrocarbon treatment and production installations and in particular in fixed or floating off-shore production installations.
In fact, on leaving the nose-piece of the torch, the oil or the condensates carried along by the gas are set on fire and fall flaming back down on to the installation or in the immediate vicinity thereof, thus endangering the whole installation and the lives of the whole of the staff.
This danger is all the more important, in off-shore installations, since the staff risk being imprisoned on the platform or the floating burning support and since further the oil or the condensate floating on the sea may form a sheet of fire prohibiting any possibility of evacuation.
To try to eliminate this risk, one of the best arrangements used up to present is formed by placing, between the liquid hydrocarbon driving source and the nose-piece of the torch, three capacities, namely a separator, a safety purifying installation and a torch foot tank, mounted in series in the gas flow chain, these capacities being respectively equipped with three high level detection devices which cause, should the liquid level exceed a predetermined height, closure of the hydrocarbon feed of the installation.
Furthermore, in such an installation, the torch foot tank has, or may have, a liquid retention capacity, such that it allows sufficient time for the hydrocarbon feed valves of the installation to be closed manually.
However, it is clear that in any case, principally in the case where the torch is vertical or subvertical on the production support, the safety of the staff and of the whole of the platform will depend:
on the operation of the automatic detection and mechanical actuation automatic devices which are always subject in time and depending on the operating conditions to break-downs, and
as a last resort, on the time in which the liquid is retained in the torch foot tank, which is dimensioned with respect to the anticipated duration of human intervention, which is always problematic and the hazardous character of which does not conform to good safety logic.
Furthermore, it should also be noted that the torch foot tank, which is generally placed in a low part of the installation, because of its dimensions risks causing considerable, even inacceptable inconvenience.